I bought an On-One 456-evo and left it standard for ages….the spec was good for a sub thousand pound UK steel hardtail.
It had their own seatpost, Truvativ bars, lock on grips, short stem (Truvativ again), decent saddle (comfy!), High Roller tyres front and back, coil spring Sektor fork (awesome, air forks wish they couild be this good!), 2 x 10 SRAM drivetrain…
…and Avid Elixir brakes.
This gave me cause for concern but they were sharp from the start and had incredible power, great feel, nice lever design….then i took them off one day to do some maintenance, changed the pads etc….and they turned to crap instantly, spongey feel, no bite, no power despite pulling the lever virtually to the bar!…the LBS bled them, they were slightly better but nowhere near the standard they arrived from On-One…i sold them and bought Deore-615’s like everybody else.
…have transferred lots of the parts to my current Ragley and they’re still doing great service.